Biodegradable paper battery powers ingestible devices for three days in pigs

Researchers demonstrated a swallowable paper-like battery that powered medical devices inside pigs for up to three days before its biodegradable components broke down. A small version powered an experimental RFID tag, while a larger one powered a capsule that stimulated the stomach and increased the hormone ghrelin without visible tissue damage at the stimulation site. The layered battery uses a magnesium-alloy anode, a molybdenum-trioxide and activated-carbon cathode, a biodegradable electrolyte and wax coatings that regulate degradation. Capacity remains low, performance varied between units, and the non-biodegradable circuit board passed through the animals rather than dissolving.